将含有低拷贝数的mini—F replicon、一个卡那霉素抗性基因和一个lacZa基因8．6kb的DNA片段经同源重组 置换到棉铃虫核型多角体病毒基因组中的多角体蛋白基因内，构建了既能在E．coli内复制又可在昆虫细胞内复制 形成完整的病毒粒子棉铃虫核型多角体病毒Bacmid(HaBacmid—HZ8)。另外将HaSNPV的多角体蛋白基因和P10 启动子序列取代pFastBacDual质粒上的AcMNPV的多角体启动子序列和P10启动子序列，构建插入HaSNPV多 角体蛋白基因和P10启动子序列的HapFaStBacPhP10供体质粒。利用HapFaStBacPhP10供体质粒将eGFP基因转 位至HZ8的Tn7附着位点上，随后将含有eGFP基因的重组HaBacmid DNA转染至HZAml细胞内。转染5d后， 细胞核内能形成典型的多角体，在萤光显微镜下观察到细胞内显示出强烈的绿色萤光。结果证明我们构建的 HaBac to Bcac表达系统能有效的表达外源基因。

A 8．5kb fragment containing an E ．coli low—copy number mini F replicon，a selectable kanamycin resistance marker and lacZ gene with attTn7(the target site for bacterial transposon Tn7) replaced polyhedrin gene in HaSNPV genome using homologous recombination．HaSNPV genome was cloned and maintained as 1 32 kb bacterial artificial chromosome(Bacmid)in E．coli，transfection of the Bacmid(HaBacmid．HZ8)into HzAml cells led to a productive virus infection．In this paper．the donor plasmid HapFastPhP10 was constructed using the Ha—polh gene and the Ha．P10 promoter tO re． place the original Ac P1 0 promoter and Ac—Polh promoter of the pFastBacDual donor plasmid respec． tively．The eGFP gene was inserted into multiple cloning site(MCS)downsream of the P10 promoter in the pFastBacHaPhpP10 donor plasmid．Recombinant HaBacmid HZ8 was constructed by transpo s． ing a mini—Tn7 element from a HaDFastPhP1 0 donor plasmid tO the mini．attTn7 attachment site on the HaBacmid—HZ8 when the Tn7 transposition functions are provided in trans by a helper plasmid．Re． combinant HaBacmid．HZ8 DNA was transfected HzAml cells．occlusion bodies and green flusecent were found within HzAml cells 5 days after transfection．The results indicated the Habac to Bac ex． pression system based on HaSNPV can effectively express foreign gene．